I am trying to recharge the air conditioning on my 2010 Chevy Avalanche LTZ and I have run into a problem. What I think is the low pressure port, I can’t get the quick release on the Freon can to connect. The only other port is attached to the evaporator. Can someone help me identify wher the low pressure port is? I have attached a picture of the compressor lines. Or do I need a special connector?

Which cap is low pressure?

 

Low port is the larger schrader valve.

 

low port is on the accumulator...the port with green dye on it.
you can"t see the evaporator...its in the hvac case in the passenger compartment

 

Thank you so much

 

wash the dye off when you are done. if it goes green after washing...you have found the leak point.